Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Phosphorous Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed1990

[The evaluation of commercially available silane coupling agents for porcelain adhesion].

We investigated the effectiveness of commercially available silane coupling agents on the adhesion between the composite resin and the porcelain. As silane coupling agents, we used Cosmotech primer. Clearfil porcelain bond. Porcelain liner M, and Scotchprime. As porcelain, we used Cosmotech porcelain DA2 which was etched either with hydrofluoric acid or with phosphoric acid gel. The tensile bond strengths between composite resin and the porcelain treated with silane coupling agents were measured after one day immersion in 37 degrees C water. Among the silane coupling agents, Clearfil porcelain bond gave the highest bond strength of about 175 kgf/cm2. When any of these silane coupling agents were used, the bond strengths were increased more by hydrofluoric acid etching than by phosphoric acid etching. Especially in the case of Scotchprime treatment, hydrofluoric acid etching was remarkably effective on the increase in the bond strengths. The value in hydrofluoric acid etching was 3 times higher than that in phosphoric acid etching. From SEM observation, hydrofluoric acid etching gave greater roughness to the porcelain surface, which resulted in greater mechanical interlocking of the resin. In the case of Cosmotech primer treatment, the combination with GC bonding agent did not increase the bond strengths, while combination with Clearfil new bond did. The phosphoric acid ester monomer in Clearfil new bond, which is known as strong acid, was supposed to catalyze the activation of silane coupling agent.

Adhesives↗
PubMedDate not supplied

The influence of various conditioner agents on the interdiffusion zone and microleakage of a glass lonomer cement with a high viscosity in primary teeth.

The smear layer, which occurs during cavity preparation procedures, does not constitute a stable substructure in the bond of restorative material to dental hard tissues. Depending on the dissolution of this material in the course of time, microleakage occurs between the tooth and restorative material. This study evaluated the effects of different conditioner agents (Fuji Cavity Conditioner, 10% maleic acid, 35% phosphoric acid and 3% hydrogen peroxide) on Fuji IX microleakage, Fuji IX-enamel and Fuji IX-dentin combination in Class I cavities prepared to standards having the dimensions of 4x3x2 mm3 in extracted primary molars. The restorations were then subjected to thermocycling procedures and soaked in the 0.5% basic-fuchsin dye for 24 hours. Some sections were taken, parallel to the long axis of the tooth in a mesio-distal direction, and evaluated under a stereo-microscope for leakage. Also, two samples of Fuji IX-enamel and dentin combinations were chosen randomly from each group for evaluation in scanning electron microscopy (SEM). The distribution of microleakage occurred as follows: Control Group > Hydrogen Peroxide > 10% Maleic acid > Fuji Cavity Conditioner = Phosphoric acid. The difference between microleakage scores obtained from the groups was statistically significant (p<0.05). The SEM evaluation revealed a close interface connection in all groups except for the control and hydrogen peroxide groups in the Fuji IX-enamel combination. In the Fuji IX-dentin combination, however, a close interface connection was observed except in the control group. In conclusion, the application of conditioner agents to Class I cavities restored with glass ionomer cement with a high viscosity in vitro either diminishes or completely eliminates microleakage.

Acid Etching, Dental↗
PubMedDate not supplied

Comparison of the metabolism of parathion by a rat liver reconstituted mixed-function oxidase enzyme system and by a system containing cumene hydroperoxide and purified rat liver cytochrome P-450.

The metabolism of parathion by a reconstituted mixed-function oxidase enzyme system (rat liver cytochrome P-450, NADPH-cytochrome c reductase, dilauroyl phosphatidylcholine, deoxycholate, and NADPH) or a cumene hydroperoxide system (cytochrome P-450, dilauroyl phosphatidylcholine, and cumene hydroperoxide) have been compared. The products formed on incubation of parathion with both systems were paraoxon, diethyl phosphorothioic acid, diethyl phosphoric acid, p-nitrophenol, and atomic sulfur. The apparent KM values for parathion for formation of paraoxon and diethyl phosphorothioic acid with the cumene hydroperoxide system were 55 and 39 X 10(-6) M, respectively. These KM values are not significantly different. When the reconstituted system was used, apparent KM values of 2.8 x 10(-6) M for formation of paraoxon and 3.9 x 10(-6) M for The formation of diethyl phosphorothioic acid and diethyl phosphoric acid were determined. These KM values are also not significantly different. covalent binding of the sulfur atom, released in the metabolism of parathion to paraoxon, to the proteins of the reconstituted system and to cytochrome P-450 of the cumene hydroperoxide system was also examined. With both the reconstituted system and the cumene hydroperoxide system approximately 65% of the sulfur released became bound to the proteins of these enzyme systems. The binding of the sulfur atome resulted in a progressive inhibition of the metabolism of parathion by these two systems.

Animals↗
PubMedDate not supplied

Determination of insoluble, soluble, and total dietary fiber in foods and food products: interlaboratory study.

A collaborative study was conducted to determine the insoluble dietary fiber (IDF), soluble dietary fiber (SDF), and total dietary fiber (TDF) content of food and food products by using a combination of enzymatic and gravimetric procedures. The method was basically the same as that developed for TDF only, which was adopted official final action by AOAC, except for changing the concentration of buffer and base and substituting hydrochloric acid for phosphoric acid. These changes were made to improve the robustness of the method. Duplicate blind samples of soy isolate, white wheat flour, rye bread, potatoes, rice, corn bran, oats, Fabulous Fiber, wheat bran, and a high fiber cereal were analyzed by 13 collaborators. Dietary fiber values (IDF, SDF, and TDF) were calculated as the weight of residue minus the weight of protein and ash. The coefficients of variation (CVs) of both the independent TDF determination and the sum of IDF and SDF were better than 15 and 18%, respectively, with the exception of rice and soy isolate. These 2 foods, however, contained only about 1% TDF. The CVs of the IDF were equally good, except for Fabulous Fiber, for which filtration problems occurred. The CVs for the SDF were somewhat high, but these products had very low SDF content. There was excellent agreement between the TDF determined independently and the TDF determined by summing the IDF and SDF. The method for separate determination of IDF and SDF requires further study. The modifications (changes in concentration of buffer and base and the use of hydrochloric acid instead of phosphoric acid) to the official final action method for TDF have been adopted.

Bread↗
PubMed2004

Effect of blood contamination on shear bond strength of brackets bonded with a self-etching primer combined with a resin-modified glass ionomer.

This study assessed the effect of blood contamination on the shear bond strength and bond failure site of a resin-modified glass ionomer (Fuji Ortho LC, GC Europe, Leuven, Belgium) used with 3 enamel conditioners (10% polyacrylic acid, 37% phosphoric acid, and self-etching primer). One hundred twenty bovine permanent mandibular incisors were randomly divided into 8 groups; each group consisted of 15 specimens. Two enamel surface conditions were studied: dry and contaminated with blood. One hundred twenty stainless steel brackets were bonded with the resin-modified glass ionomer. After bonding, all samples were stored in distilled water for 24 hours and then tested in shear mode on a testing machine. The groups conditioned with self-etching primer and 37% phosphoric acid had the highest bond strengths for both dry and blood-contaminated enamel. The groups conditioned with 10% polyacrylic acid showed significantly lower shear bond strength value, and the unconditioned groups had the lowest bond strengths. For each enamel conditioner, no significant difference was reported between dry and blood-contaminated groups. Significant differences in debond locations were found among the groups bonded with the different conditioners. Blood contamination of enamel during the bonding procedure of Fuji Ortho LC did not affect its bond strength values, no matter which enamel conditioner was used.

Acid Etching, Dental↗
PubMed2003

Effect of smear layer on root demineralization adjacent to resin-modified glass ionomer.

The cariostatic effect of resin-modified glass ionomer (RMGI) on secondary root caries is well-documented. However, this beneficial effect may be dependent upon the mode of cavity surface treatment. To investigate this relationship, we studied 4 cavity surface treatments prior to the placement of RMGI: no treatment (None), polyacrylic acid (PAA), phosphoric acid (H(3)PO(4)), and Scotchbond Multi-Purpose adhesive (SMP) as a control. Specimens were aged for two weeks in synthetic saliva, thermocycled, and subjected to an artificial caries challenge (pH 4.4). Polarized light microscopy (PLM) and microradiography (MRG) showed significantly less demineralization with the H(3)PO(4) cavity surface treatment as revealed by ANOVA and Tukey's multiple comparisons (p < or = 0.05). Dentin fluoride profiles determined by electron probe microanalysis (EPMA) supported PLM and MRG findings. It may be concluded that removal of the smear layer with phosphoric acid provides significantly enhanced resistance to secondary root caries formation adjacent to RMGI restorations.

Acid Etching, Dental↗
PubMed1984

Factors affecting the assay of histone H1 and polylysine by binding of Coomassie blue G.

Although a mixture of calf thymus histones or the H2B and H4 fractions gave values in the Bradford assay that were similar to those for bovine serum albumin, low values were obtained with histone H1 and polylysine. The assay was found to be more sensitive for histone H1 and polylysine if the phosphoric acid concentration in the reagent was decreased or the polypeptide solutions contained low concentrations of nonionic detergents. Substitution of perchloric acid or hydrochloric acid for phosphoric acid and alcohol in the Coomassie blue G reagent provided an assay that was similar in sensitivity for histone H1 and a total histone mixture. It was suggested that the degree of metachromasia with Coomassie blue G may serve as a probe of conformational changes in histone H1.

Animals↗
PubMed2005

Effects of salicylic-lactic acid conditioner on the shear bond strength of brackets and enamel surfaces.

The purpose of this study was to evaluate the effects of salicylic-lactic (SL) acid conditioner on the shear bond strength of brackets. Fluoride releasing (Light-bond) and non-fluoride releasing (Enlight) composite adhesives were used after conditioning with 0.22% salicylic + 9% lactic acid or 34% phosphoric acid. Composite adhesives were light cured with either a halogen light curing (HLC) unit for 30-50 s or a plasma arc curing (PAC) unit for 4 s. The shear bond strength was measured with an Instron. Failure modes of debonded brackets were identified based on adhesive remnants on the bracket and tooth. Salicylic-lactic acid conditioning was found to provide adequate shear bond strength. Groups conditioned with SL acid were debonded mainly at the enamel-resin interface and comparatively clean enamel surface after debonding was observed than those conditioned with phosphoric acid. Using confocal laser scanning microscopic examinations, it was found that demineralization patterns between SL acid and phosphoric acid conditioned groups were not different when the same adhesive was used. The SL acid conditioner did not reduce the demineralization. Light-bond adhesive showed less demineralization than Enlight adhesive. The PAC unit can be recommended as an alterative to the HLC unit because it significantly reduces the irradiation time.

Acid Etching, Dental↗
PubMed2002

Effect of surface treatments on the bond strength of glass ionomers to enamel.

OBJECTIVES: The objective of this study was to evaluate the effect of various surface treatments on the bond strength of several glass ionomers to enamel, and to examine the resulting bond interface. METHODS: Ground bovine enamel specimens were divided into groups which were pretreated with one of the following: (1) no pretreatment, (2) Vitremer primer, (3) 10% polyacrylic acid or (4) 35% phosphoric acid. A conventional glass ionomer and two resin-modified glass ionomers (RMGI's) were bonded to the pretreated enamel surfaces, stored in water for 24h and shear bond strengths measured. RMGI's were tested as light-cured and self-cured materials. Transverse sections of similarly prepared samples were etched with phosphoric acid for 60s to partially remove enamel and expose the enamel/glass-ionomer interface. The interface morphology was examined by SEM. RESULTS: Polyacrylic acid and phosphoric acid conditioning resulted in significantly increased bond strength to enamel for all three glass ionomer materials, compared to no pretreatment (p<0.01). Light-cured bond strengths were in most cases, significantly greater than when self-cured (p<0.01). Examination of the bonded interfaces revealed the presence of polymer tags in the enamel conditioned with polyacrylic acid and phosphoric acid. SIGNIFICANCE: Conditioners significantly improved the bond to enamel for the conventional glass ionomer and RMGI's that were examined in this study. Micromechanical bonding may play a role in the mechanism of bonding glass ionomer to enamel.

Acid Etching, Dental↗
PubMed2003

Immunocytochemical analysis of dentin: a double-labeling technique.

Immunocytochemical analysis is a fundamental and selective technique for identifying different molecular components of human dental structure. The hypothesis tested here is that the application of different etching solutions on dentin does not hinder collagen fibrils and proteoglycans from maintaining their immunochemical antigenicity. Human dentin disks were treated with 0.5M of EDTA, citric acid, maleic acid, or phosphoric acid (for 15 or 30 s). A double-immunolabeling technique was performed to identify, simultaneously, collagen fibrils and chondroitin sulfate. The use of different acids resulted in different degrees of labeling. Maleic and citric acids revealed a diffuse and intense labeling for both collagen fibrils and proteoglycans. The use of phosphoric acid on dentin showed a massive coagulation of the proteoglycans (15 s) or very low labeling (30 s). These data clarify that the use of acids on dentin components is able to modify their antigenicity. Moreover, the double-labeling immunocytochemical technique allows understanding of the spatial relationships between the collagen fibrils and proteoglycans of the dentin matrix.

Animals↗
PubMed1995

Effects of a barbituric acid/CuCl2 initiator system on resin adhesion to dentin.

The effectiveness of a barbituric acid/copper (II) chloride initiator system in dentin was examined in terms of the effects of barbituric acid structures and dentin conditioners on bond strength. Curing times and tensile bond strengths to bovine dentin were measured for PMMA/MMA resins in conjunction with initiators consisting of a combination of CuCl2 and four barbituric acids having different substituents. The dentin surfaces were treated with six conditioners consisting of 10% citric acid or phosphoric acid with or without 3% FeCl3 and CuCl2. Among the four barbituric acid systems studied, curing times varied significantly (p < 0.002), but the bond strengths to dentin, conditioned with 10% citric acid containing 3% CuCl2, did not (p > 0.60). The dentin conditioners influenced bond strength significantly (p < 0.02). The phosphoric acid based conditioners produced higher bond strengths than those based on citric acid. The bond strengths obtained under optimal conditions were comparable to those reported for MMA-TBB resin. Thus, the resin applied using the barbituric acid/CuCl2 system worked as well as one of the most effective bonding resins available.

Acid Etching, Dental↗
PubMed1981

Meta-phosphoric acid-its use in the selective extraction of RNA from fixed tissue sections.

This communication presents a new quick method for selective extraction of RNA from formalin-fixed tissues, such as kidney, intestine, ovary and testis of white rat and liver of rodents, Tatera indica and Millardia meltada and of the frog, Rana tigrina as well as of human wart. Sections of pancreas and kidney fixed in acetic acid-alcohol were also tried. The method is to treat deparaffinised sections in 20% and 15% meta-phosphoric acid at 5 degrees C for 10-20 and 20-30 min, respectively, and then to stain nuclear DNA with 0.5% aqueous solution of methyl green, methylene green, Giemsa, toluidine blue O or 0.125% pyronin G for 2 min, rinsed with water, treated with n-butanol for 2-3 min, cleared in xylene and mounted. It has been found that liver sections of rodents require 24 hours of treatment in 15% cold meta-phosphoric acid for complete removal of RNA, whereas those of the frog require only 20 min at 20% acid. It has been concluded that following treatment of sections in cold meta-phosphoric acid, RNA is extracted selectively leaving DNA in a native state. Therefore, staining of DNA in tissue sections from which RNA has been extracted is due to binding of its negatively charged phosphate groups with the positively charged dye molecules.

Animals↗
PubMed1991

[Soluble elastin and antibody formation].

In the present study, we have obtained antibodies in rabbits to peptides prepared by digestion of elastin with either oxalic acid or phosphoric acid. By Elisa assay, we have shown the lowest production of antibodies against elastin-derived peptides prepared by digestion of N-elastin with phosphoric acid. We have found a strong cross-reactivity between antibodies obtained to peptides prepared by different digestion of insoluble elastin from bovine ligamentum nuchae or aorta and these antigens. A less pronounced cross-reactivity was observed in case of elastin-derived peptides from porcine aorta.

Animals↗
PubMed2000

Acidified sodium chlorite antimicrobial treatment of broiler carcasses.

An acidified sodium chlorite (ASC) solution was investigated for its antimicrobial effects on broiler carcasses processed under conditions similar to those used in U.S. commercial poultry facilities. Of particular interest was the ability of the ASC solution to reduce natural bioburden in a prechill procedure. A number of parameters such as pretreatment washing of carcasses with water (no wash versus water wash), ASC concentration (500, 850, and 1,200 ppm), method of application (spray versus dip), and method of acid activation (phosphoric acid versus citric acid) were explored to evaluate disinfection conditions. ASC dip solutions (18.9 liters) were freshly prepared for groups of five prechill eviscerated carcasses per treatment (n = 10 carcasses). ASC treatment was shown to be an effective method for significantly reducing naturally occurring microbial contamination on carcasses. Reductions following immersion dipping were demonstrated at all disinfectant concentrations for total aerobes (82.9 to 90.7%), Escherichia coli (99.4 to 99.6%), and total coliforms (86.1 to 98.5%). Additionally, testing showed that ASC solutions maintained stable pH and minimal chlorite ion concentration deviations throughout each treatment. The results of the parameter evaluations indicated that maximal antimicrobial activity was achieved in carcasses that were prewashed and then exposed to a 5-s dip in a solution containing phosphoric acid- or citric acid-activated ASC. At 1,200 ppm ASC, a mild but transitory whitening of the skin was noted on dipped carcasses. The results support the methods currently approved by the U.S. Department of Agriculture for the use of ASC solutions as a prechill antimicrobial intervention in U.S. poultry processing plants.

Animals↗
PubMed1998

Effects of acid-etching on the tensile properties of demineralized dentin matrix.

OBJECTIVES: Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity (E) of human coronal dentin matrix. METHODS: Small hour-glass shaped (for UTS) or l-beam shaped (for determination of E) were prepared from mid-coronal dentin of extracted human third molars. After protecting the ends with varnish, the middle of the specimens was completely demineralized in 0.5 M EDTA (pH 7). UTS was determined by tensile stressing to failure. Modulus of elasticity was calculated from stress strain curves. The results were analyzed by ANOVA and Student-Neuman-Keuls test at the 95% confidence level. RESULTS: Brief (ca. 1-2 min) exposure of demineralized dentin matrix to acids had no measurable effects on its tensile properties. Ten-minute exposures to 2.5% and 17.5% nitric acid lowered (p < 0.05) the UTS compared to phosphate buffered saline (PBS)-exposed controls. Exposure of the decalcified dentin to 10% citric acid containing 3% ferric chloride, 10% citric acid, 37% phosphoric acid or 17.5% nitric acid containing 3% ferric chloride for 10 min had no effect on UTS. None of these acids consistently lowered stiffness. SIGNIFICANCE: The results indicate that relatively long exposures to acids are required to alter the tensile properties of demineralized dentin. It is unlikely that the brief exposures to acids that are used in adhesive dentistry would acutely weaken the physical properties of demineralized dentin. However, long-term studies should be done to determine if such treatment increases the susceptibility of the matrix to hydrolysis.

Acid Etching, Dental↗
PubMed2002

Rapid-extraction oxidation process to recover and reuse copper chromium and arsenic from industrial wood preservative sludge.

Chromated copper arsenate (CCA) wood preservative can form insoluble sludges when the hexavalent chromium component is reduced by wood extractives, wood particles and preservative additives in the solution. This sludge accumulates in treating solution work tanks, sumps and in-line filters and must be disposed of as hazardous wastes by waste disposal companies at high costs. A number of commercial sludges were investigated and found to contain 18-94% copper, chromium and arsenic as oxides combined with sand, oil, wood particles, additives and wood extractives. We have developed a multi-stage recycling process whereby approximately 97% of the CCA components are recovered from the sludge. It involves extraction with sodium hypochlorite to remove and oxidize chromium (more than 90%) and extract most of the arsenic (approx. 80%) followed by extraction of the copper and remaining arsenic and chromium with phosphoric acid. The phosphoric acid extract contains some trivalent chromium, which is subsequently oxidized by sodium hypochlorite. The combined oxidized extract containing CrVI, CuII and AsV was compatible with CCA treating solutions and could be re-used commercially for treating wood without having a significant effect on the preservative fixation rate or the leach resistance of the treated wood. A cost analysis showed that the economic savings from recovery of CCA chemicals and reduced landfill costs exceeded the variable costs for materials and energy for the process by as much as Can $966 per tonne of sludge if sodium sulfite can be acquired in bulk quantities for the process.

Arsenates↗